There are various definitions of the therm of algorithm. Study the text at the link - Algorithm.
The algorithm can also be an accurate description of all elementary actions that are necessary to perform in order to achieve a particular process. The algorithm can be written by
  • Ordinary spoken language
  • Pseudo code
  • Graphic symbols
When you finish writing the algorithm using common spoken language or pseudo code for a particular process for which is necessary to write a computer program, follows writing Algorithm using standard graphic elements.
This is necessary because such representation of an algorithm can be understandable to every developer on the planet and based on it, it is possible to write a computer program in any programming language.
For computer programmers the algorithm written using graphic symbols represents "Graphic representation of program flow."
To write the algorithm we use standard graphic elements where each of them represents a specific step in the program.
This refers to the standard accepted worldwide and understandable to any computer programmer.
The graphic
shows only several graphical elements that are commonly used when writing algorithms.
The first element is a Line of program flow that connects graphic elements and ends with an arrow that shows the direction in which the process, or program continues. Specifies the sequence of steps in the algorithm, and the computer program.
Other graphical elements are understandable by themselves.
Elements Start and End program are identical and mark the beginning and end of program.
Element Input represents data entry from the keyboard, HD, CD or any other place where the data are retrieved from.
Element Operations represents the step in which individual actions are executed in the pseudo code or the computer program, adding two numbers, assigning values ​​to a variable, etc.
Element Condition represents prerequisite step for conditional branching in computer program.
Within this element we can ask questions ,'If...  then... else...', and determine future course of the execution of computer program based on the answers.
The default is that an affirmative answer extend program flow down and negative to the left or right.
Also the question must not be ambiguous.
Element Output represents the data output, write results in a variety of devices, usually monitor, printer ...
Other graphic elements used in making Algorithm you can see attached to this page.
All the best,